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In most centers, artificial limbs are constructed in a modular fashion.1 The stump is placed in a thermoplastic socket that is then fitted into the main body of the limb. The bulk of the prosthesis comprises a metal frame with articulations and an outer casing of acrylic resin or carbon composite material. Before fitting the limb, many patients place their stump in a liner designed to reduce friction on the skin. This may be an expanded plastic cup, a silicon/mineral oil sleeve, or a cotton or nylon sock. The prosthetic limb, once fitted, is held in position by one of a range of suspension elements. In above-knee (Fig. 96-1) or proximal arm amputations, this is usually a fabric belt arrangement worn around the waist or shoulders, respectively. Below-knee amputees require a different system using either a butyl rubber sleeve or corset to hold the appliance firmly onto the thigh (Fig. 96-2). Many patients with above-knee amputations now use a suction socket device that provides sufficient suspension by holding the prosthesis in place through negative pressure without the need for additional belts (see Fig. 96-1).
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Limb prostheses are the subject of continual technological development particularly in the field of bionics. Myoelectric devices, for example, rely on skin contact with electrodes to detect neuromuscular signals that can be converted to artificial limb movement. Neuroprosthetic devices involve implantation of electrodes into neural tissue usually through the skin, for example, cochlear implants. Such devices are under development for prosthetic limbs. These devices thus have the potential for causing skin problems.
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The skin of an amputation stump is not designed to withstand the physical insults it encounters within a prosthetic limb. For example, although some adaptation to friction or pressure occurs, some skin problems are inevitable. If these dermatoses cannot be prevented or rapidly resolved by prosthesis adjustment or medical intervention, they can incapacitate the patient, particularly those who have lower limb, weight-bearing prostheses. As a result, patients may suffer social isolation, emotional distress, or even financial deprivation if they are unable to work.
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Skin problems may occur ...